1992 yamaha 3hp 3MSHQ

[robert53a]

Hi, Just acquired this little motor and noticed it has no tell tale and very little spray from upper exhaust relief, but doesn't get hot(checked with imfa red gun) there is a hole in the bottom of the upper bracket that looks like a tell tale spout. Is it supposed to have a water streaming telltale? Thanks

 

[Ostsideend]

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I compare to my 1996 3 HP 2 stroke Malta (6L5) wich should be the same...

Some water should come out of the bore.

Use a piece of wire or so to open the bore if it is blocked.

There is a thermostat in the cylinder wich could stay open or does not exist.

For how to change the impeller on that small motor i did a foto docu. Look at pics here (they are self explaining): http://boote-wassersport-forum.de/showthread.php?7159-Impeller-Tausch-beim-Aussenborder

 

[robert53a]

Thanks Ostisdeend, I did find the thermostat a little sticky and have since pulled, cleaned and tested it in a pan of hot water. It opens and closes now. I put a new impeller in and it didn't change anything. It still runs cold with no spray unless I go full throttle for a minute or two. This motor sure churns up my 80 gallon barrel. But the hottest spot on the motor was 125 degrees F. just below the head on the cylinder wall. I'll try the wire and see what happens

 

[Ostsideend]

No Title

125 °F = 52 °C sounds normal for the Malta to me. Look (data in °C):

The fuel tank is sitting right above the head. It is not a bad idea to let him run cool ;-)
Fuel consumption is poor. He realy likes a smaller main jet (difficult to find one) and/or a much higher compression. (geometrical 11:1) A lot of work (but makes fun to me) There are usually up to 0.5mm left to be reduced on the head, still ahving a 0.9mm gap between piston OD and head (squeeze band)

Back to your topic... you will be qable to push a wire approx 6 oer 7 mm into the bore, Do NOT widen the bore diameter! It goes directley into the water coolant channel behind the impeller pressure. If it becomes to large, you will loose coolant flow through the motor.
I cant explain why sometimes the little water pie does come out after the motor heats up and not at any time. I do have seen this effekt on some maltas. Some does, some not.

Oliver

 

[Ostsideend]

Have a short look to an old vid i took.
Your temp. is fully OK.

http://www.youtube.com/watch?v=670G0zTiLBM

This motor got a external exhaust system, just for fun, to look nice and to give a nice sound to my tender rubber boat.

 

[Ostsideend]

No Title

Last but not least, and if i am not wrong, this is the way of the coolant from water pickup via the impeller upwards and out:

Dont get confused. There is a self made flange for external exhaust gas flow and a opening for that through the upper gearcase section...

 

[Ostsideend]

Edit: put your motor deeper into your basin. lets say put it until the water level reaches 10 cm above cavitation plate. the water pee should come proplery. i today purchased another malta and tested. hes has this effekt too. put him deeper and it stops...

 

[robert53a]

Thanks for all the information. I think this 3hp is configured a little different than the Malta. I recieved a tackle box with the motor and inside this tackle box I found spare spark plugs, extra zinc anodes a emergency pull rope and the orignial owner's manual for this motor. On page 35 & 36 it shows a diagram of the telltale discharge the 2Q, 3Q and 4Q motors. the 4Q has a pilot hole in the same place as your malta. The 3Q is say to check for discharge water at the exhaust relief holes. I did find you video interesting was that a tune exhaust on that motor? WOW

 

[Ostsideend]

Yes it is a resonance tuning exhaust (just for fun)

Probably they changed their design after 1992. On the weekend i got a 1993 3HP having the telltale hole drilled in.

A pleasure to give information. I also got a lot of helpful information out of this forum. So i try to pay back a little.